Tracking analog-to-digital converter

Abstract

The present invention herein describes a tracking analog-to-digital converter, in particular of the differential input type. In an embodiment thereof the tracking analog-to-digital converter, having a differential analog input including a first analog input and a second analog input, and a digital output at a first number of bits comprising: a back and forth counter having a direction input and an output, with a second number of bits; a digital-to-analog converter having a data input coupled to said output of said converter, a reference input and an output, with a second number of bits; a first comparator having a positive input, a negative input coupled to said output of said digital-to-analog converter and an output coupled to said direction input; characterized in that said reference input is coupled to said first analog input and said positive input of said first comparator is coupled to said second analog input.

What is claimed is:  
     
       1. Tracking analog-to-digital converter, having a differential analog input including a first analog input and a second analog input, and a digital output at a first number of bits comprising: 
       a back and forth counter having a direction input and an output, with a second number of bits;  
       a digital-to-analog converter having a data input coupled to said output of said converter, a reference input and an output, with a second number of bits;  
       a first comparator having a positive input, a negative input coupled to said output of said digital-to-analog converter and an output coupled to said direction input;  
       characterized in that  
       said reference input is coupled to said first analog input and said positive input of said first comparator is coupled to said second analog input.  
     
     
       2. Tracking analog-to-digital converter in accordance with  claim 1  characterized in that said first analog input and said second analog input are coupled to the inputs of a second comparator that produces in output a signal corresponding to the sign of the signal of said differential analog input; said first analog input and said second analog input are selectively coupled to said positive input of said first comparator and selectively inverted coupled to said reference input. 
     
     
       3. Tracking analog-to-digital converter in accordance with  claim 2  characterized in that said first analog input and said second analog input are selectively coupled to said positive input by means of a first switch commanded by said sign of the signal of said differential analog input and are selectively inverted coupled to said reference input by means of a second switch commanded by said sign of the signal of said inverted differential analog input. 
     
     
       4. Tracking analog-to-digital converter in accordance with  claim 2  characterized in that said first number of bits corresponds to said second number of bits plus 1. 
     
     
       5. Tracking analog-to-digital converter in accordance with  claim 1  characterized in that said first number of bits corresponds to said second number of bits.